Your fireplace ashes can be recycled in your garden

Nov. 10, 2012

Perhaps with the promise of cold weather, you are ready to bring in the logs and light up the fireplace. Wood fires are nice, cozy and great for keeping the thermostat low, but now and then you need to remove the ashes to get a good fire going. What to do with them?

Jane McCune asked me this question last spring because they burn their fireplace most of the time and it seemed to her that the ashes could be recycled someway. The answer is yes, they can for the most part and no in a few small ways.

Before I start with all the fun ideas, firefighters caution everyone that a paper or plastic bag is never the best way to dispose of ashes. Even if no sparks appear, the best way to carry them out of the house and out of the garage or off the porch or deck is in a covered metal pail. Let them sit for a few days before you use them, just to be safe. I have read that when a house has burned from fireplace ashes, sometimes the only thing left is the bag of ashes.

On the other hand, if you have a cold frame some distance from buildings and want to warm up the plants, putting the covered metal bucket inside the frame middle may keep everything quite toasty for up to 24 hours.

Wood ashes are a homemade source of potassium, some phosphorous, calcium, boron and other elements and itís all free. It is also very alkaline and works much like lime to raise the pH in the soil.

It does not contain nitrogen, though. When wood burns, nitrogen and sulfur are lost. But you can still use it on your lawn, scattered lightly and followed by good watering as the ash filtered into the soil has nutrients that grass can use. It also seems to promote the growth of clover, which provides nectar for bees. A win-win situation there.

Apple trees like a spread of ashes around their base. In fact, hardwoods, such as apple, produce three times as much ash per cord as do softwoods. Itís like returning this valuable material right back to its source.

In the spring or summer, encircling your plants with a ring of ash about 6 inches from the stem helps ward off slugs and snails. Most vegetables and flowers can use this potassium rich by-product except for your acid lovers, such as azaleas, rhododendrons and blueberries. A mound around ferns or rhubarb protects them in winter and the rain and snowmelt eventually carries it deeper into the root system.

If you have acid soil, digging in the ashes will make it more strongly alkaline. You can use ashes to make a tea for tomatoes. Put about five pounds of ashes in a cloth bag, tie securely and put it in a 50 gallon garbage can filled with water. Once a week, when the plants begin to flower, dip in the watering can and pour a cupful around each plant.

A few cautions, though. Donít use ashes on potato gardens as it may promote potato scab. Donít scatter ash on windy days. If you use ashes on your lawn, wait a month before using nitrogen fertilizers as the fertilizers lose nitrogen when mixed with the pH in wood ash. Try not to lump it in piles as it becomes too concentrated for some plants. Ashes from briquettes in the barbecue, coal or fake logs are off-limits as they contain chemicals. A little, just a little, can be added to the compost pile, especially if you have oak leaves or pine needles in there. Sprinkle the ash between the compost layers.

Judy Terry is a freelance garden writer. Questions or comments should be sent to her at Iowa City Press-Citizen, P.O. Box 2480, Iowa City, IA 52244-2480; faxed to 834-1083; or emailed to life@press-citizen.com.